Ah ha! Thanks

: : I was at the local diner last night where I was talking to a waitress who was using the word "yous" as a sort of plural form of "you". "I didn't know yous was coming in tonight." The only other people, besides New Yorkers, I have heard use this are Irish friends from the UK. (I'm pretty sure it comes from Irish immigrants in NY) So I'm wondering, could this be an archaic plural for of "you", or is it just quirky and wrong?

: Here's a long entry from Terence Patrick Dolan's Dictionary of Hiberno-English:

: YOUS, also YIZ, plural of 'you.' In [the] Irish [language] there is both a singular and a plural second person pronoun, as there used to be in English, with 'thou' as the singular and 'ye' as the plural. The form 'you' was originally the accusative and dative plural of 'ye.' From the 14th century it became customary to use the plural form, 'you,'in addressing superiors in place of 'thee' and 'thou'; from the 15th century, 'you' began to be used in place of 'ye.' From the time large numbers of Irish people became exposed to English, in the late 16th century and onwards, the 'you' form was therefore the normal form of address to a single person. As regards the verbal forms, there is evidence that in the 17th and 18th centuries some people tried to distinguish between singular and plural by making changes to the verb: we thus find 'you is' and 'you are'; but this useful device was abandoned in the interests of so-called purity of the language. Confronted with this bewildering volatility in the use and formation of the second person pronoun, it would appear that Irish speakers of English decided to distinguish singular from plural by attaching the plural signal 's' to the singular 'you', on the analogy of regular pluralisations such as 'cow' - 'cows'. 'Yous all better be back here on the dot of six o'clock or we're leaving without ye.' Joyce, 'A Mother' (Dubliners, 160): 'He said "yous" so softly that it passed unnoticed'; Doyle, The Van, 20: 'Did yis have your dinners at half-time or somethin?'